Ofsted inspections of schools could be reduced to just once every 10 years, it emerged yesterday, as part of a radical shake-up being planned by the education watchdog.

The second largest teaching union, the National Union of School Masters Union of Women Teachers, heard at its annual conference in Jersey yesterday that the change was "on the cards" as a result of a consultation between the office for standards in education and teachers' representatives.

Signalling a new era of cooperation with Ofsted - and in particular with the new chief inspector of schools, Mike Tomlinson - the NASUWT's outgoing president, Martin Johnson, told delegates that "salvation" was in sight.

Speakers had described how teachers' lives had been ruined by the stress and trauma of regular Ofsted inspections.

Most schools face inspection every six years, or every four when they cause concern.

A motion drawn up nearly a year ago - before the departure of Chris Woodhead, the controversial former inspector, last November - recommended industrial action pending "fundamental reform" negotiated with the NASUWT.

But yesterday Mr Johnson told delegates any protest must be ruled out because of the changes signalled by Mr Tomlinson, who took over from Mr Woodhead in a one-year appointment.

A consultation document is expected to be published after the general election. Nigel de Gruchy, general secretary of the NASUWT, welcomed the new spirit of cooperation.

"Mike Tomlinson has brought a positive attitude to the job," he said. "Chris Woodhead would have his feet up on the desk and tell you to 'push off'. His body language was openly insulting."

A spokeswoman for Ofsted said: "We are preparing a consultation document but have made no decisions on the length of inspection cycles."

 A 16-year old boy who lost a high court attempt to force his teachers to teach him was yesterday given the right to appeal.

The boy's mother took the NASUWT to court after staff refused to teach him because of alleged disruptive and violent behaviour.